It has been pointed out that dental plaque adsorbed onto teeth is an important factor causing gingivitis. To eliminate the dental plaque, it has been a practice to physically cleaning the oral cavity by brushing, etc. However, it takes a long time to clean the oral cavity by brushing and the dental plaque-controlling effect thus achieved is still insufficient.
Under these circumstances, studies have been made to develop oral compositions such as dentifrices containing bactericides so as to achieve supplemental effects of eliminating the dental plaque. In particular, it is known that cationic bactericides are efficacious in preventing the formation of dental plaque. However, cationic bactericides can be hardly processed into preparations due to the poor compatibility with other components in compositions. To overcome this problem, it has been recently proposed to add water-insoluble noncationic bactericides (triclosan, etc.), which are highly compatible with other components in compositions, to oral compositions.
When compositions containing such water-insoluble noncationic bactericides are packed in containers made of synthetic resins, however, the stability of these bactericides is lowered with the passage of time and the bactericidal effects are deteriorated due to the adsorption of the bactericides onto the inner wall of the containers, etc.
To solve this problem, JP-A-20288820, JP-A-6-92830 and JP-A-6-279248 propose to prevent the adsorption of nonionic bactericides onto containers by improving the containers, for example, with the use of specific polymers as the innermost layer of the containers (the term "JP-A" as used herein means an "unexamined published Japanese patent application").
On the other hand, JP-A-8-198623 discloses that porous calcium carbonate having excellent properties of absorbing oil and water has been developed and are usable as a food additive. However, it has never been proposed so far to use this porous calcium carbonate in oral compositions for stabilizing bactericides, eliminating dental plaque, perverting halitosis, etc.